Police in Iran have arrested six young people for posting a video online of them dancing to Pharrell Williams’ hit song “Happy,” showing them on state television as a public warning to youth in the Islamic Republic.

In the Tehran video, three young men and three young women dance on a secluded rooftop, a stairwell, a walled-off driveway and a chic apartment, wearing sunglasses and silly clothes while laughing and smiling. The women wear no hijabs.

Tehran police chief Hossein Sajedinia confirmed on state television late Tuesday that the six people were detained over the video. State television also aired blurred pictures of the video and then showed the six with their backs turned toward the camera.

Sajedinia said the video clip “hurt public chastity” and prompted police to launch a swift investigation.

Pharrell Williams responded on his Facebook page: “It is beyond sad that these kids were arrested for trying to spread happiness.”